Pen point



Patented May 5, 1936 UNITED STATES PATENT OFFICE PEN row No Drawing.Application May 13, 1935 Serial No. 21,189

1 Ola -n.

This invention relates to pen points, and the invention is especiallyconcerned with a novel type of gold plated pen point.

Heretofore, it has been quite common to employ solid gold pens or nibsin fountain pens,

and solid gold pens of this type have certain advantages, particularlywith respect to corrosion resistance, smoothness of ink fiow, andappearance. These pens, however, must obviously be relatively expensive,and the present invention has in view the provision of a relativelyinexpensive pen point having the advantages of the solid gold type ofpen.

For this purpose I prefer to make, my improved 1 5 pens from a chromiumalloy steel, such as the so-called corrosion resistant steel alloyswhich are usually chiefly comprised of chromium, nickel and iron, and toapply a gold plate thereon by electrodeposition. Corrosion resistantalloys of 29 the type in question may also contain smaller amounts ofother ingredients added for the purpose of improving the corrosionresistance and other properties of the product. An alloy which I findespecially suitable for pens is one contain- 25 ing about 18% chromium,about 8% nickel and about il /2% molybdenum. By gold plating such analloy I am enabled to secure a high degree of acid resistance,smoothness of ink flow and also gold appearance. Furthermore, my imwproved pen, being made of a very tough alloy steel, is very durable andnot readily damaged or worn.

In considering the nature of this invention, esspecially the manner inwhich my pen is rendered 35 substantially corrosion .proof and acidresistant,

it should be borne in mind that all plating, applied as byelectrodeposition, is porous. In view of this, if the base metal onwhich the plating is deposited is subject to attack by acid ingredients40 in ink, the plated pen would also be subject to such attack, the rateof attack being only very slightly reduced by the presence of the porousplating. However, the base metal of my improved pen is of a corrosionproof or acid re- 5 sistant nature, because of the oxide film whichnormally forms on such alloys, so that even though the gold plating(which, as will hereinafter appear, is applied to the oxide film) isporous, the pen is not subject to attack by acids.

50 It should further be noted that considerable difiiculty has beenencountered in the past in satisfactorily applying a plating of the typehere in question to alloy steels of the so-called stainless type whichare characterized .by the forma- 55 tion of an oxide film on the exposedsurfaces.

This difiiculty resulted. from several causes, one of which is probablythe fact that the oxide film which forms under usual or normalconditions, is' of a spongy, friable or fragile nature. In any event,this normal type of oxide film does not ad- 5 here tenaciously to themetal, so that attempts to ,apply a plate thereon have beenunsuccessful.

The plating of such attempts, in fact, is so lacking in adherentproperties, that even slight rubing, as with a finger, is frequentlysufficient to 10 remove the deposited metal. I have also found that theusual type of gold plating solutions employed in many industries areunsuccessful in applying an adherent gold plating, probably because ofthe alkalinity of the usual gold plating solution which apparently hasthe effect of even further increasing the spongy and non-adherent natureof the oxide film almost immediately upon immersion of the articles intothe plating solution.

With the foregoing factors in mind, I first form the pens from asuitable chromium alloy tough, dense and highly adherent oxide filmthereon. Nitric acid may be employed for this purpose and the acid maybe used either to toughen the relatively spongy and non-adherent filmnormally present on the alloy or to produce a new film (after removal ofthe usual spongy 3O film), which new film also is i a highly adher entcharacter. The acid may be used in concentrated form or in a solutioncontaining as low as 5%, or even lower, although the time of treatmentmust be increased with the low concentra- 5 tions. Ordinarily from about5 to 10 minutes in a solution containing upwards of 10% nitric acid willbe found to be sufficient.

Following this treatment, I immerse the pens in a plating bathcontaining free hydrocyanic acid. This may be accomplished by exlploying a bath containing the following ingredients in about theproportions indicated:

Concentrated hydrochloric acid pint 1 Sodium cyanide ..ozs. 8 Sodiumgold cyanide oz. A; Water gallon 1 I have found that the presence offree hydrocyanic acid is an important factor in providing an adherentdeposit. The quantity of this acid prescut is not critical. Preferablythe bath should contain sufficient to give a slight acid reaction tolitmus, and the quantity may be carried up at least to an amountequivalent to that which will tervah or in some other equivalent manner.

prepared a bath with the proportions of ingredients listed above, Iprefer to renew the supply of hydrocyanic acid either by adding anadditional supply of sodium-cyanide at periodlc'in- As a guide indetermining when additional sodium cyanide is necessary, the brillianceof the deposit may be observed. when the deposit noticeably loses itsbrilliance, additional cyanide should be added. Ordinarily, in theaverage plating bath of fifteen gallons capacity, it is sufllcient toadd a few ounces of sodium cyanide for each 500 gross of pens plated.

It is of importance in this process to ensure that the plating commencesimmediately upon 3 immersion'of the articles in the plating solution,this, apparently, for the reason that the nature of the plating bath issuch as tends to destroy or impair the toughness and adherence oi theoxide combine with the gold present. Having initially film. With inmind, the cathode connection should be made or completed to the articlebeing I plated prior to immersion of the article in the.

bath. Following the first deposit of gold, I preter'to' apply anadditional gold'plate which may conveniently be done in the more usualtype of plating solution containing, for example, ounce sodium goldcyanide, and 2 ounces sodium cyanide per gallon of water.

Attention is directed to the fact that the method herein disclosed isalso disclosed and claimed in my copending application Serial No.21,190, filed May 13, 1935.

I claimy I A pen point composed of a chromium alloy steel having a'denseandadherent oxide film thereon and further having an adherentelectrolytically deposited gold plate applied to said film.

HIRAM B. LUKENB.

